Continuous kiln.



r. I). SHAW. CONTINUOUS KILN. APPLICATION FILED FEB/16, 19 10.

Patented Nov. 25, 1913.

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F 0% 2 W020? .1 w W n06 5 Inventor F. D. SHAW.

CONTINUOUS KILN.

. APPLICATION IILI-ID FEB. 16, 1910.

1,079,443, Patented NOV. 25, 1913.

3 SHEETS-SHEET 2. J F W Wfifinesses: [77997-71507;

F. D. SHAW.

CONTINUOUS KILN.

APPLICATION FILED PEB.16, 1910.

1,079,443, Patented Nov. 25, 1913.

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FRANCES n. snhw, or (intense, imitators, hssremoa 'ro snllw mm? comm-NY,or

ATLANTA, enomm, A conromtrm'n or GEORGIA.

conmmnotrs KILN.

Specification 6! Letters Patent.

Patented Nov. 25, 1913.

Application filefi res-mew 16', ion. Serial No. 544,183.

a part of this specification.

My invention relates "to continuous kilns, and has special reference tokilns which are adapted to burn brick and various forms of pottery.

Many attem ts have been made, particularly in the brick industry, todecrease the time which is necessary for the proper burning of brick.According to the system which has been most generally employed, thebrick are piled up in a kiln which is slowl heated in order to drive outthe water which is mechanically contained in the clay or other substanceof which the bricks are manufactured. The heat of the kiln is graduallyraised until finally the maximum temperature is attained, and the firesare then drawn and the kiln with its contained brick is graduallyallowed to 'cool. This method of burning necessitates the use of a largeamount of time, and has the further objection that the brick are notburned uniformly. Each brick of course remains in exactly the sameposition throughout the entire burning oper ation, and inasmuch as it isimpossible to obtain the same heat in all parts of the kiln there isgreat lack of uniformity in the product which is obtained.

It has long been recognized that the two inherent disadvantages of theordinary form of kiln, namely, the excessive heat required in burningand the lack of uniformity in the product obtained, might be overcome bythe useof continuous kins. 1 It is necessary, in order to provide anefliclent continuous kiln, that there 'should be a combinationof,various features. The brick to be burned should be placed on a car orother movable sup ort, and with a steady movement passed t rough-thekiln, first entering a drying chamber, here the water mechanically heldinthe clay or other material of which the brick is formed, is drivenoff: The brick are then passed'intoa zone" of the kiln where they aregradually subjected to, an increasing temperature until temperaturenecessary to effect the vitriiying action-is attained.

e third zone consists of that portion of the kiln Where the heatgradually decreases the brick are finally delivered from "the I orderthat the heat in the kil may be readily controlled, have found it ofadvantage to employ a plurality ofstacks addi'ti'onfto the main stack ofthe kiln. By means of these subsidiar stacks it is possible to withd'rawthe hot gases from the kiln as desired, and thus obtain a more e finallythe maximum cient regulation of the temperature than would b possible ifreliance were plac d entirely on the regulation of the "source of heatand the damper in the main stack.

It has been recognized by those skilled in the art that the mosteilioient method known up to the present time for transporting the brickthrough the kilnconsists in the use of cars on which the brick ma bepiled. In order to prevent the cars iiom warping excessively and beingund'ul'y heated b the action of the flame, these cars have been providedwith a heat-insulating portion which forms the bottom of the heatingchamber of the kiln, and means have been provided for sealingcommunication between the heatin chamber and that'portion of the kilnwhich lies below the cars. In order to obtain eflicient results I havefound that it is essential'that the seal between the heating chamber andthe lower portion of the kiln should be as eflectiv'e as possible. Ihave found that a sand seal betweenthe sides of the cars and the walls,of the kiln gives excellent results, it often be;

advisable to mix a certain percentage of ta c with the sand in order toallow the downwardly projecting sealing members of the cars. to passeasily through the sand seal.

the ends of the cars, I have einployed a special form of brick, so thata tongue. on one car will fit into a, correspondi groove of the brick onthe adjacent car. y means of the seals which have "just been mentioned,cold air is prevented from being drawn from the lower part of the'kilnintothe heating chamber. I114 or" er to propel the cars (ion- In orderto provide an efiicient seal bet-ween its tiniio'usly through the kiln Ihave found that the best resultsare obtained by the use of a'c'ontlnuous cable'lwhich passes over suit able sheaves near the ends ofthe kiln. The

carsare individually gripped to this cable \by means of a specialform-"of grip which will be described hereafter, and on reaching theeduction end of the kiln the cars are 5 automatically ungripped from thecable,

and by meansof any of the well-known transfer cars may be moved to asecond. re-

' turn'track, and after the burned brickshave been removed, the variouscars may be returned-to the entrance of the kiln by a cable running inthe opposite direction from that which is within the kiln, and afterbeing loaded with brick are ready to again pass through the kiln.

Great difliculty has been experienced in properly drying the brick asthey pass through the first or drying zone within the kiln. It isevident that a considerable v amount of water must be driven from thebrick, and in order to prevent the condensation of the resulting steamin the main stack I have found that condensing means in con-' nectionwith the drying chamber itself should be employed. In order to effectthe desired rqsult I construct the condensing chamber of sheet-iromsteelor other suitable metal, the roof of the chamber consisting of twostraight sides which come to- .gether at a comparatively acute angle.The steam which has been formed from the water within the bricks, onstriking this metallic roof, condenses, and by means of suitable troughsit is caused to flow out of the drying chamber. In order to stillfurther facilitate this action and also to prevent the roof fromwarping, I have found it of advantage to water-cool the outside of theroof, thus keeping the metal at a comparatively constant temperature.

40 As pointed out above, one of the disadvantages of the stationary'kilnis the lack of uniformity which is obtained in the heat to which thebrick are subjected. Similar results will be obtained in a continuouskiln unless suitable means are provided by which the heat is evenlydistributed across the kiln.

' That is, it is necessary that the bricks toward the outside of theheating chamber should be subjected to the same heat as those nearer thecenter line. To attain this result I employ a special form of damper inconnection with the main stack. This damper operates across the entirekiln and serves to cause the .hot gases to pass to substantially thesame extent on the sides and through the central line of the kiln; Adamper. is provided on each side of the ,stack so that the flow of gasesmay be regulated, as desired, through the portions of the kiln lying oneither side so of the stack. p

It/has been customary in many forms of to employ an oil burner which hasa flame direct ass through the k1 Such a method of 5' Beating is veryunsatisfactory, in that it line 7-7 of Fig. 1. Fig. 7 is a detail sec- 3of the side walls of chamber B, these walls y impin%illlg .on the brickas they water is introduced in the gas generator with the oil, thegasesare caused to burn comparatively slowly, and after being introducedinto the kiln the slowly burning gases afford heat through a muchgreater length of kiln than is possible by the use of the ordinary formof burner.

These and other advantages of my invention will be more apparent byreference to the accompanying drawings, in which- Figure 1 is adiagrammatic plan view of my continuous kiln. Fig. 2 is an enlargedsectional view on the line 2-2 of Fig. 1. Fig. 3 is an enlargedsectional view on the line 3-3 of Fig. 1 showing a car of brick inposition within the kiln. Fig. 4 is a fragmentary side elevationof aportion of the kiln showing the gas generators and burning chambers.Fig. 5 1s a sectional view on the line 55 of Fig. 4:. Fig. 6 is a sideelevation showing the method of preventing the passage 0 air betweenadjacent cars. Fig. 7 is an enlarged sectional view on the tion on line7 a of Fig. 7. Fig. 8 is a plan view showing the method forautomatically removing a car from itsconnection with the cable. Fig. 9is a pers ective view of certain metallic strips 0 inverted V-shapedcross-section. I

As shown most clearly in Fig. 1, the kiln has two distinct portions,first, the portion A, which forms the drying chamber, and second, theportion B, which consists of a heating and cooling chamber, and extendsfrom the chamber A to the eduction end of the kiln. The portion 13 ofthe kiln has the side walls 1 and the arch 2. At the portion areconsiderably thickened in order to alford suflicient space for theburning chambers which will be described hereafter.

As shown in Figs. 1 and 7, the main stack 4 communicates through theroof 2 with the inside of the kiln. A damper 5 is provided on each side.of the stack 4, and is operated by means of the wheel 6, which isrigidly mounted on the end of shaft 7. The pinions 8, 8 are suitablymounted on the shaft 7, and cooperate with the racks 9, 9 which aremounted on the damper 5. It is thus evi-.

damper 5 may be raised or lowered as desired,-'and the, passage of gasesfrom the kiln to the stack may thus be regulated. By the use of suchdampers it is evident that the draft is distributed evenly across. thekiln, and for this reason all of the bricks which are in any giventransverse plane are subjected to the same amount of heat. 7

v The general construction of the inside of the kiln is clearly shown inFigs. 2 and 3. A sheave 10 is provided near each end of the kiln, and acable 11 passes over these two sheaves. One of the sheaves ismechanically driven by any of the well-known means, so

that the cable 11 is continuously in motion.

The construction of the inside of thekiln is such that a pit 12 isformed, through which the cable 11 passes. This pit is made ofsuflicient size, so that it is readily possible for a man to walkthrough the same. The brickwork of the inside of the kiln is built abovethe pit 12 in such manner that the' ledges 13, 13 and 14, 14 are formed.On the ledges 13, 13, are mounted the rails 15, 15, considerable spacebeing left between the ends of adjacent rails in order to allow forexpansion and contraction caused by variations in temperature. Theserails are not rigidly fastened to the ledges 13, 13, but are so fastenedwith spikes that the rail is, allowed to expand and contract longitudiwnally without displacing the spikes. To the ledges 14, 14 is secured theinverted V- shaped strip of sheet metal 16, which forms a trough betweenone of its sides and the side of the kiln, in which the sand 17 isplaced. Through the length of the kiln there are a number of thesesho'rtinverted V-shaped strips 16, which overlap each other and are attachedto the ledge 14 by means of nails or other suitable fastening means,which pass through slots 16 in the metallic strips, as shown in Fig. 9.In this way the expansion and contraction of the strips 16 is providedfor, with no danger of causing buckling when the temperature isincreased.

Mounted on the tracks 15, 15 is the car 18, from .the sides of whichthere are downwardly projecting flanges 19, 19, which pass into the sandseals 17, and in this way prevent passage of gases from the portion ofthe kiln chamber lying below the car 18' to the portion of the chamberlying above the car. In order to allow an easy passage of the flanges19, 19 through the sand 17 as the car is being moved, I find it ofadvantage to mix a considerable percentage of tale with the sand. Thecar 18 .is provided on its upper surface, with a plurality of firebricks 20, 20, these bricks having corrugations 21 on their uppersurfaces, as best shown in Fig. 3. These corrugations extendlongitudinally of the car, so that the hot gases passing through thekiln are allowed to go underthe bricks 22.which are placed on thecorrugations 21 of the fire bricks 20. The fire bricks on the two sidesof the car ferent vertical are provided with lateral projections 23,which extend under shelves 24, 24 projecting from the side of the kiln.A small amount of sand 25 may be placed on the projections 23 in orderto still further add tot-he efficiency of the sand seals. As shown inFigs. 3 and 6, the fire bricks 20 are joined by means oftongue-and-groove joints. In order to aid in keeping the bricks 20 cool,holes 26 pass longitudinally through the bricks and register with eachother on ad- ,jacent cars.

position by means of one of the grooves 30.

It'is clear that as the cable exerts its pull on the car, the cam 29will be forced to grip the cable 11 more firmly as more and morepressure is exerted) When the car approaches the end of the kiln, thehandle 31 strikes a trip 32 which is rigidly mounted on the kiln. Theeffect of this trip is to automatically turn the cam 29 so that thepressure on the cable 11 is released and the car is no longer moved bymeans of the cable, but by means of the pressure of the next car behind.At the point where the curve, as shown most clearly in Fig. 8, and

in this way the hook 28 is moved into a difplane from that occupied bythe cable 11. In this way the car is automatically entirely freedfrom'the cable. As

explained in the preamble of this specification, after the carpassesthrough the kiln ,it is moved by a transfer car to a second trackwhich returns it to the entrance end of the kiln. This operation is wellknown in the art, however, and it is unnecessary to describe it furtherin this connection.

As explained above, the portions 3, 3 of the Walls 1, 1 are constructedsomewhat thicker than the remaining portions of these walls in order toallow sufficient space for the gas generators and burning chambers whichare placed therein. The exact relation of these. parts is shown mostclearly in Figs. 4 and 5.

The gas generator consists of a pan or dish-shaped vessel 33 havingflaring edges 34. This pan rests on the bottom of chainber 35 within thewall 3, the front of this collar 36 having the flange 37 is-supportedfrom thebrick-work ofthe kiln, so that the chamber being open to theatmosphere. A l

lower edge of the collar 36 is within the dish-shaped vessel 33, butwith the lower edge of the collar somewhat above the bottom of vessel33. The main oil pipe 38 is supplied with branch pipes 39, in which areplaced the valves 40. The oil coming through the pipe 39 enters thefunnel 41 and;

passes downwardly through pipe 42 into the dish-shaped vessel 33. Theupper end of the collar 36 communicates with the opening 43 leading intothe burning chamber 44, which in turn communicates through the port 45with the heating chamber of the kiln. The burning chamber 44 is suppliedwith a front wall 46, in which there is ordinarily placed a peep-hole47, closed by the brick 48. A pipe 49-is supplied with water, in which asmall amount of ammonium nitrate or other similarchemical is dissolved,

by means of the pipe 50 communicating with the barrel 51 in which thesolution is placed. A great variety of salts may be used to form thesolution above mentioned, the object of which is, first, to make thecombustion of gas slower by introducing Water into the oil which isbeing gasified,

' and, second, the presence of a salt has the effect of facilitating thevitrifying action.

I have found that a very small amount of the salt is sutlicient, andordinarily I use about a half pound in a barrel of water, but I do notwish to confine myself to this particular amount, as it may be variedwithin very wide limits. Communicatin with pipe 49 are the pipes 52supplied with valves 53, the solution from the main pipe 49 therebybeing conducted through pipes 52 into the funnels 41. The oil and thewardly into the combustion chamber 44, the

products of combustion thence passing into the burning chamber of thekiln itselfx As shown in Fig. 4, a considerable number of gas generatorsof the type which I have described are used on each side of the furnace,the burners on opposite'sides preferably being placed opposite to eachother rather than in staggered positions, although the latterarrangement may be used. I'Vhen the gases enter the main burning chamberof the kiln itself, the presence of steam delays the combustion so thatthe heat is distributed along the length of the furnace to a muchgreater extent than in the case of furnaces of prior construction.

In order to afford regulation of the heat in the kiln the stacks 54, 54are provided in thewalls 1, 1, these stacks being equipped with dampersof any well-known type. When it is desired to lower the temperaturebetween the stacks 54, 54 and the main stack 4, the dampers of stacks54, 54 are opened, and the hot gases pass from the kiln into thesestacks, thereby bringing about the desired action. The connectionbetween the main kiln chamber and these stacks is shown in Fig. 2. Afurther regulation of heatis obtained by means of stacks 55, 55 placednear the point of junction of the main kiln B and the dryingchamber A.These stacks may be used to withdraw the gases from the drying chamber Awhen it is not desired to have all of such gases pass into the mainstack 4. It will be evident that by means of the dampers 5, 5 used inconnection with the main stack 4 and the stacks 54, 54 and 55, 55 anexcellent regulation of the heat in the kiln is obtained.

The drying chamber A is preferably constructed as shown in Fig. 3, theroof consisting of' two mctallicsheets 56, 56, preferably of iron orsteel, which are joined at the peak 57. The troughs 58, 58 and 59, 59are provided in connection with the sheets 56, 56, and have a slopetoward the entrance end of the drying chamber A. As the water is drivenout of the bricks 22, the steam thus formed condenses on the inside ofthe sheets 56, 56, and-the moisture runs down and is collected in thetroughs 58 58 and 59, 59, and thus conducted out of the drying chamberA. In order to further facilitate this operation and prevent themetallic roof of the drying chamber from warping, the plpes 60 areprovided, these, pipes connecting w th the main 61 These pipes areprovided with perforations 62 so that when water is turned on,- thiswater will flow through the perforations in thepipes 60, 60, and serveto keep the roof water-cooled.- Although I have described thisparticular form of roof as being very advantageous, it is by no meansnecessary that the drying chamber should be constructed in the way thatI have described, inasmuch as I have found that it is feasible to havethe drying chamber of the same construction as the mam portlon of thekiln, the water which is expelled from the drying bricks bein partlyabsorbed by the fire brick of the rying chamber and partly passingoutwardly through the stacks of the kiln. When'such a construction isused, however, I have found that more or travel through the kiln variesgreatly accord ingto the length-01f the kiln, the kind ofbrick which arebeing burned, the temperature employed, and the distribution of theheat. In; ordinary practice, however, with a kiln having atotal' lengthoftwo hundredfeet,

including the drying chamber, I have found that aspeed of about one footper minute gives excellent results when burning brick of sandand-lime.As the car enters the drylug-chamber A, the heatgradually increases asthe car travels onward in its course. The effect of this heat is togradually dry the brick, the water which is expelled being formed intosteam, which, as explained above, condenses on the metallic sheets 56,

. iififorming the roofof the drying chamber.

It is very important that the drying opera- $10!) should be thoroughlyperformed, mas much as when the brick pass to the burning portion B ofthe kiln, if the mechanically held water has not been thoroughlyexpelled, the sudden increase of heat will cause steam to be formedwithinthe brick, and a violent disruption or explosion ofthe brick isapt toltake place. In many of the kilns of the prior art it has beencustomary to use a comparatively narrow kiln and pile a great manybricks on the cars which are travelmg through the kiln. In this way ithas been impossible to conduct a proper drying operation in the dryingchamber, for the reason that the amount of' Water to be expelled fromthe brick is so excessive that the heat available and the time duringwhich the bricks remain in. the drying chamber are insuiiicient torop'erly perform the operation. In my served that the kiln iscomparatively broad,

preferably not less than twice the height ofthe arch above the car top,and when burnmg sand lime brick only a single layer of brick is placedon the car. When ,burning clay brick, on the other hand, more than onelayer will be built up on the car, but even under such conditions theconstruction of the kiln is such that the gases obtain free access tothe brick, anchthe amount of water to be evaporated is not so excessivebut that it IS readily taken care of in the drying chamber. From thedrying chamber A, the car next passes into the main burning zone of theportion B of the kiln. As explained above, the distribution of the heatmay be regulated by means of the dampers 5, 5 of the main stack 4 andthe dampers of the stacks 54, 54 and 55, 55. The heat graduallyincreases in the kiln until the car reaches a of the walls 1, 1. In thisportion of the kiln 1111, however, it will be obposition opposite theportions 3, 3

will be evident; that on account of the loca tion of the main stack 4,none of the gases passing from the gas generators in the thickened walls3, 3 will pass into the cooling zone, althougha large/amount ofheatpasses into this zone by radiation and onaceount,v

of absorption of heat by the walls of the kiln from the hot brick whichhave passed from the heating zone of the furnace. When the car reaches aposition near the eduction end ofthe kiln, the handle 31 of the grip29strikes the trip 32, and inasmuch as the car passes slightly in alateral direction on accountof' the curve in the track, the cable 11 isfreed from the book 28. After being freed from the cable 11 the car ispushed onwardly by means of the adjacent car to its rear, which is stillattached to the cable 11.. The brick are next unloaded from the car,andv by any of the well-known means the car is once more returned to theentrance end of the kiln, where it is loaded with brick and once morepasses through thekiln. In order to facilitate passage of the carsthrough the kiln. and to lessen the eifect, of the sand seals in theresistance which they offer to the downwardly rojectinoflanges of thecars, I prefer to have a slight pitch in the kiln, which ordinarilyamounts to from nine inches-to a foot per hundred feet ofkiln length.

In this's ecifioation I have given a somewhat broa is evident that manychanges could be made in the detailed construction without departingfrom the spirit of my, invention.

Although I- have described my kiln particularly with reference to itsuse in connection with burning brick, it is evident that the same formof kiln could be used for burningany kind of ceramic material, or can beused for the treatment of metals, as, for example, in annealing or othersimilar processes.

What I claim as new and desire to cover by United States Letters Patentis:

1. In a continuous kiln, the combination of a kiln chamber in the formof a rectilinear passageway open at the ends and provided with a mainexhaust passage opening from the top of the kiln chamber into theoutside atmosphere at a point toward one end of the. kiln chamber, afurnace receiving its air supply from the outside atmosphere anddischarging into the kiln chamber approximately midway between the endsthereof, and two. dampers one immediately adjacent to each side of theopening from the kiln chamber into the exhaust passage, each damperextending across and ardescription of my kiln, and it v ranged to beadjusted in a vertical plane within the kiln chamber to restrict thekiln passageway but to permit a constant draft therethrough.

1 ing fastened at one .point in its length to the tunnel wall, the saidstrips on either side of the tunnel forming with the tunnel wall atrough into which the aprons depending from the car tops extend, thesaidtroughs being adapted to contain sand to constitute a sand sealbetween the car top and the tunnel walls.

3. In a continuous kiln, in combination, a kilnchamber in the'form of atunnel, a shoulder on each side of said tunnel, a car forpassing throughsaid tunnel, said car being constructed and mounted so that a partthereof will pass under said shoulder, and sand disposed upon the-partsof said car passing under said shoulders.

4. In a continuous brick kiln, the combination of a rectilinear tunnelof substan tially uniform cross-section from end to end, a plurality ofclosely adjacent but in-' dependent furnaces openinginto the upper partof said tunnel at or near the center of the length thereof, an exhaustflue opening from the top of the tunnel at or near one end thereof, avertically adjustable damper at either side of the opening from thetunnel into the said exhaustflue, the said dampers being immediatelyadjacent to either side of the said exhaust flue opening, a plurality ofcars with tops of fire-resisting material, means for moving the saidcars continuously in close juxtaposition to one anotherthrough the saidtunnel from end to end thereof, the direction of movement being from theexhaust flue end of the tunnel towardthe said furnaces, and means forsealing the joint between the car tops and theside walls of the tunnel.

5. In a continuous brick kiln, the combination of a rectilinear tunnelof fire-resist- 1ng material having vertical side walls and an archedroof, a plurality of furnaces arranged on either side of the tunnel ator near the middle of the length thereof, and each opening into the saidtunnel, an exhaust flue opening from the said tunnel at or near one endthereof, a plurality of abutting cars,-. the wldth of the car tops beingsubstantially eqilal to the width between the walls of the tunnel andadapted to form the floor of the tunnel, and the width of the tunnelbetween the walls being more than twice as great as the height ofthe'arch above the car tops, and means for moving said cars through thetunnel from end to end thereof in a direction toward the furnaces fromthe exhaust flue end of the tunnel.

. 6. In a continuous kiln, a substantially rectilinear tunnel-like kilnchamber, a plurality of cars adapted to travel through the tunnel, metalaprons depending from either side of the car tops, and a. plurality ofde? tached sheet-metal angle-plates mounted at either side of thetunnel, successive angleplates overlapping one another, each angle-.plate being fastened at one point in its length to the adjacent tunnelwall, the said angle-plates on either side of the tunnel forming a trouh into which the aprons depending from t e car tops extend, the saidtroughs thus formed being adapted to contain sand to constitute a sandseal between the car tops and the tunnel walls.

7. In a continuous kiln, a substantially rectilinear tunnel-like kilnchamber, a plurality of cars adapted to travel through the tunnel, metalaprons depending from either side of the car tops, troughs mounted uponthe side walls of the tunnel and into which troughs the said metalaprons depend, and a mixture of sand and talc contained in the saidtroughs to constitute with the said metal aprons a seal between the cartops and the tunnel walls.

8. In a continuous kiln, a rectilinear tunnel-like kiln chamber havinside walls and of each car top registering with the corrugations of theadjoining car-tops, the said corrugationsproviding openings throughwhich gases' may be passed under the wares mounted'upon the car tops.

In witness whereof, I hereunto subscribe my name this 14th day ofFebruary, 1910.

FRANCES D. SHAW.

Witnesses:

ARTHUR H. Bon'r'rormn, LEONARD W. NOVANDER.

